package demo2;

import java.util.*;

public class Test1 {
    public static void main(String[] args) {
        List<Integer> list = new LinkedList<>();
        list.add(11);
        System.out.println(list.remove((Integer) 12));
        System.out.println(list);
        Map<Integer,Integer> map = new TreeMap<>();
        map.put(12,1);
        map.put(121,1);
        System.out.println(map.size());
    }
}
